Oil can be recovered from microorganisms, such as microalgae, using wet extraction methods or dry extraction methods. In dry extraction methods, microorganisms are typically harvested and dried before oil extraction. However, drying is an expensive and energy-intensive process. Also, if the oil is rich in polyunsaturated fatty acids (PUFA) (e.g., for food and nutritional supplement applications), the process can cause significant oxidations of the PUFA due to high temperatures involved in drying.
Furthermore, dry extraction methods of recovering oil from microorganisms typically are conducted with organic solvents, such as hexanes, and require coupling with mechanical cell disruption methods for suitable oil yields. However, mechanical disruption methods are expensive and energy intensive, while organic solvents are flammable, toxic, and must be removed from the end oil product.